Portable data collection device with variable focusing module for optic assembly

ABSTRACT

A portable data collection device including an imaging assembly including a two dimensional (2D) photosensor array. The imaging assembly is selectively actuatable with a first trigger for reading a target dataform in the imaging assembly&#39;s target area and actuatable with a second trigger for capturing a image of the target object in the target area. The device also includes an illumination assembly including an circuit board assembly supporting illumination and targeting light emitting diodes and a lens array or panel positioned adjacent the circuit board assembly for focusing an even pattern of illumination on the target area and generating a crosshair illumination pattern for aiming the device at the target dataform. The device further includes an optic assembly for focusing reflected illumination from the target area onto the two dimensional photosensor array. The optic assembly includes a focusing optic for changing a best focus distance of the optic assembly as a function of moving a wedge shaped optic with respect to a stationary optic to change a thickness of the focusing optic.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of copending U.S. application Ser.No. 09/197,175, filed Nov. 20, 1998, entitled “Portable Data CollectionDevice With Variable Focusing Module For Optic Assembly” and is acontinuation-in-part of U.S. application Ser. No. 08/824,288, filed Mar.26, 1997, entitled “Portable Data Collection Device With VariableFocusing Module For Optic Assembly”, now abandoned and U.S. applicationSer. No. 08/797,552, filed Jan. 31, 1997, entitled “Portable DataCollection Device With Crosshair Targeting Illumination Assembly”, nowissued as U.S. Pat. No. 5,949,057 on Sep. 7, 1999. The aforesaidapplication Ser. Nos. 09/197,175 and 08/824,288 and Pat. No. 5,949,057are incorporated herein in their entireties by reference.

FIELD OF THE INVENTION

The present invention relates to a portable data collection deviceincluding a two dimensional photosensor array imaging assembly and, moreparticularly, to a portable data collection device having a twodimensional photosensor array imaging assembly selectively actuatable toread a bar code dataform and record an image of an item of interest andfurther having an optic assembly with a variable focusing module tochange a best focus distance of the optic assembly.

BACKGROUND OF THE INVENTION

Portable data collection devices are widely used in manufacturing,service and package delivery industries to perform a variety of on-sitedata collection activities. Such portable data collection devices ofteninclude integrated bar code dataform readers adapted to read bar codedataforms affixed to products, product packaging and/or containers inwarehouses, retail stores, shipping terminals, etc. for inventorycontrol, tracking, production control and expediting, quality assuranceand other purposes. Various bar code dataform readers have been proposedfor portable data collection devices including laser scanners and onedimensional (ID) charge coupled device (CCD) imaging assemblies, both ofwhich are capable of reading ID bar code dataforms, that is, bar codesconsisting of a single row of contrasting black bars and white spaces ofvarying widths. Both of these readers are also capable of reading a“stacked” two dimensional (2D) bar code dataforms such as PDF417, whichhas row indicator patterns utilized by the reader for verticalsynchronization.

A two dimensional (2D) imaging based dataform reader has been proposedin U.S. application Ser. No. 08/544,618, filed Oct. 18, 1995 andentitled “Extended Working Range Dataform Reader Including Fuzzy LogicImage Control Circuitry”, now issued as U.S. Pat. No. 5,702,059 on Dec.30, 1997. The 2D dataform reader disclosed in application Ser. No.08/544,618, includes an imaging assembly having a two dimensional arrayof photosensors or photodiodes adapted to read 2D bar code dataforms(e.g., PDF-417, Supercode, etc.) with vertical synchronization rowindicator patterns as well as matrix dataforms (e.g., MaxiCode, DataMatrix, Code 1, etc.) which do not include vertical synchronizationpatterns. The photosensors correspond to image pixels of a capturedimage frame and the terms “photosensors” and “pixels” will be usedinterchangeably. The 2D dataform reader disclosed in U.S. Pat. No.5,703,059 utilizes an open loop feedback control system including fuzzylogic circuitry to determine proper exposure time and gain parametersfor a camera assembly. U.S. Pat. No. 5,702,059 is incorporated in itsentirety herein by reference.

While using a portable data collection device to sequentially read barcode dataforms affixed to products or containers in a productionfacility, warehouse or retail store, an operator may come upon an itemwhich is damaged, incomplete, mislabeled, in the wrong location, etc. Insuch a event, it would be desirable for the operator to make a note ofthe problem item so that appropriate corrective action may be taken bysupervisory personnel. However, requiring the operator to make ahandwritten notation on a clipboard or input information concerning theitem using a keyboard or keypad of the portable data collection deviceis both time consuming and error prone. What is needed is a portabledata collection device having a 2D imaging assembly that can be actuatedto read bar code dataforms by depressing a trigger and, when a problemitem is found, the imaging assembly can be actuated with a separatetrigger to record an image of the problem item. This would enable“information”, that is, an image of the problem item, to be recordedwithout seriously interrupting the normal course of the operator's work.Additionally, it would be desirable to transmit the recorded image ofthe problem item to appropriate supervisory personnel so thatappropriate corrective action may be taken. In certain instances, it maybe sufficient to record a single frame of the image of a problem item,while in other cases, for example, if the item is larger than a field ofview or target area of the imaging assembly, it may be necessary torecord a continuous video image of the problem item to permit theoperator to record a complete view of the item. It would also bedesirable to provide an audio capture module to simultaneously capturethe operator's voice, enabling the operator to provide furtheridentification and/or commentary on the problem item to aid supervisorypersonnel in locating the item and taking appropriate corrective action.

Additionally, what is needed is a portable data collection deviceincluding an illumination assembly and a viewing assembly to assist theoperator in properly aiming and positioning the portable data collectiondevice with respect to a target object such that the target object iswithin a target area of the imaging assembly. A size of a target area ofthe imaging assembly is defined by a field of view of the imagingassembly and a distance between the imaging assembly and the targetobject. The target object may be a dataform to be read or an item to beimaged. Preferably the illumination assembly will include targetingoptics which will project a “crosshair” shaped targeting beam of visiblelight corresponding to the field of view of the imaging assembly to aidan operator in aiming the device at the target object.

A viewing assembly would permit the operator to visualize the targetarea and the target object. Visualizing the target area of the imageassembly would facilitate proper alignment of the target area and thetarget object thus insuring that the device is properly aimed. Further,visualizing the imaging target area and the target object would aid theoperator in positioning the device relative to the target object suchthat the target object is encompassed within an outer perimeter of thetarget area.

Furthermore, in package delivery applications, upon delivery of apackage, the delivery person typically uses a portable data collectiondevice to read a bar code dataform affixed to the delivered package.Normally, the delivery person also obtains a signature of the personreceiving the package. Typically, the signature of the person receivingthe package is on a sheet of paper that must be filed with the packagedelivery records or on a signature capture digitizer pad so that thesignature may electronically filed.

What is needed is a portable data collection device having a 2D imagingassembly that can be actuated to read a bar code dataform by depressingone trigger and can be actuated by a separate trigger, or applicationssoftware, to record an image of a signature of a person receiving apackage so that the signature can be filed electronically.

As an alternative to using one trigger to read a bar code dataform andusing the second trigger to image an adjacent signature block with arecipient's signature included therein a single trigger could be used toimage and decode a dataform and capture an image of the recipient'ssignature. If the dataform includes encoded data regarding the positionof the signature block with respect to the dataform, output data couldinclude decoded dataform data and data representing the portion of thecaptured image corresponding to the signature block area. What is neededis a portable data collection device that can be actuated by a singletrigger to capture an image of a bar code dataform and an adjacentsignature block, decode the bar code dataform, determine the position ofthe signature block, and output a compressed digitized representation ofthe portion of the image comprising the signature block for subsequentdownloading to a remote device.

What is also needed is an optic assembly for focusing an image of thetarget area onto a two dimensional photosensor array wherein the opticassembly includes a focusing module to permit the best focusing distanceof the optic assembly to be changed by the operator manually or changedautomatically in response to a signal representative of the sharpness ofan image of a target area.

SUMMARY OF THE INVENTION

In accordance with this invention, a portable data collection device isprovided that includes a two dimensional (2D) photosensor array imagingassembly selectively actuatable for reading bar code dataforms (bar codedataform reading mode) and recording an image of an item in the imagingassembly's target area (imaging mode). A size of the target area isdependent on a field of view of the imaging assembly and a distancebetween the imaging assembly and a target object, the object beingeither a dataform to be read or an item to be imaged. The portable datacollection device includes two trigger switches, a first triggeractuatable for reading a bar code dataform and a second triggeractuatable for recording an image of an item in the target area. In aradio embodiment of the portable data collection device of the presentinvention, a radio module is provided for transmitting an output signalto a remote device. In a batch embodiment of the portable datacollection device of the present invention, an output signal is coupledto a terminal processing board for further processing and storage.

The imaging assembly of the portable data collection device of thepresent invention further includes control and selection circuitry whichreceives input signals from an operator of the portable data collectiondevice and determines and formats an appropriate output signal. Theoutput signal may include data from a decoded dataform imaged in acaptured image frame, a compressed representation of a captured image,an uncompressed representation of a captured image, or a combination ofthese. If the desired output signal is decoded dataform data, theselection circuitry will utilize image processing and decoding circuitryto decode the dataform.

Alternately, if the desired output signal is to represent an image of afield of view of a camera assembly of the imaging assembly, theselection circuitry may output the entire frame of image data from thebuffer memory or, if appropriate, invoke a compression module tocompress the image to reduce the quantity of data to be transmitted by aradio module of the portable data collection device to a remote deviceor to be output to a terminal processing board of the portable datacollection device.

As discussed, the portable data collection device of the presentinvention includes two manually activated trigger switches forcontrolling the selection circuitry to select between a imaging capturemode and a dataform decoding mode. A first trigger switch, the dataformdecoding trigger, institutes the dataform decoding mode and signals theselection circuitry to output a decoded representation of a dataform ina captured image frame. The second trigger switch, the imaging trigger,institutes the imaging mode and has two operating embodiments. In thefirst operating embodiment of the imaging mode, depressing the imagingtrigger results in the imaging assembly capturing one frame of the fieldof view or target area of the camera assembly. In the second operatingembodiment of the imaging mode, depressing the imaging trigger resultsin the imaging assembly continuously capturing successive frames as longas the trigger is depressed.

In a third operating embodiment of the portable data collection deviceof the present invention, activation of the dataform reading triggerwill result in both decoded data and at least a portion of the capturedimage frame being output. This embodiment would advantageously beemployed in a situation where a dataform is associated with, forexample, a signature block in proximity to the dataform wherein thedataform includes encoded data setting forth the position of thesignature block with respect to some predetermined location on thedataform. When the dataform decoding trigger is actuated, an image ofthe dataform and associated signature block is captured. The dataform isdecoded and the decoded data is analyzed by the selection circuitry todetermine the location of the signature block. The output signalincludes both the decoded data and an image of the signature block.

Advantageously, the portable data collection device of the presentinvention includes a voice capture module which captures and digitizessound received through a microphone mounted on the device duringactuation of the second trigger. This feature enables an operator to“attach” a verbal message to the captured image. The digitized signalrepresenting the captured sound portion is processed by a voicecompression module prior to output to the radio module or the terminalprocessing board.

The imaging assembly includes a board camera assembly having aphotosensor array assembly including a two dimensional (2D) array ofphotosensors or pixels and a control and decoder board. The control anddecoder board includes decoding circuitry, image compression circuitry,control and selection circuitry, serial output circuitry, exposureparameter control circuitry and image buffering circuitry includingsignal processing circuitry and a frame buffer memory. The signalprocessing circuitry includes synchronization extractor circuitry andanalog to digital (A/D) converter circuitry for converting a compositevideo signal generated by the board camera assembly to digital imagedata. The decoding circuitry includes a decoder for decoding 1D and 2Dbar code dataforms. The exposure parameter control circuitry includesfuzzy logic control circuitry for controlling the frame exposure periodand gain adjustment of the board camera assembly.

The imaging assembly further includes an illumination assembly forilluminating a target item in the imaging assembly target area and anoptic assembly for focusing reflected light from the target area uponthe 2D array of photosensors of the photosensor array assembly.

The optic assembly includes a plurality of lens positioned to the frontof the 2D photosensor array for focusing reflected light from the targetarea onto the photosensor array. A shroud supports the optic assemblyand shrouds ambient illumination from the photosensor array. The opticassembly also includes a variable focusing module for varying the bestfocus distance of the optic assembly. The focusing module of the presentinvention permits clear imaging of an object as near as 5.5 inches (140mm.) from a front lens of the optic assembly to as far as 36 inches (915mm.) from the optic assembly, that is, the focusing module provides fora best focus range of 5.5 inches to 36 inches.

The board camera assembly includes the 2D photosensor array, exposureperiod control circuitry and gain control circuitry mounted on a printedcircuit board. The illumination assembly includes an array of LEDilluminators for uniformly illuminating the target area and twotargeting LED illuminators for generating a cross hair illuminationintensity pattern for aiming the portable data collection deviceappropriately. In a first embodiment of the illumination assembly, alens array is disclosed having a first targeting optics which generatesa first crosshair illumination pattern and a second targeting opticsgenerating a second crosshair illumination pattern, the first and secondillumination patterns coinciding at distance corresponding to a minimumvalue of the best focus range of the optic assembly, that is, at adistance approximately 5.5 inches (140 mm.) from the front lens of theoptic assembly. In a second embodiment, a lens array is disclosed havinga first targeting optics which generates a half frame and a crosshairillumination pattern and a second targeting optics which generates acomplementary half frame and crosshair illumination pattern. At theminimum value best focus position, the first and second illuminationpatterns combine to generate a full frame and single crosshairillumination pattern.

The device further includes a viewing assembly to further aid in aimingand positioning the portable data collection device with respect to atarget object. A pivoting member is manually pivotable into an uprightposition in a line of vision of the operator. The pivoting memberdefines an aperture. The operator holds the device at a fixed distancewith respect to his or her viewing eye and looks through the aperture toview the target object. The aperture is sized such that when an operatorviewing eye is approximately 56 millimeters (mm.) from the pivotingmember, a view seen through the aperture is substantially equivalent tothe target area of the imaging assembly. Thus, the operator mayadvantageously use the aperture both for properly aiming the device atthe target object and for moving the device closer to or further awayfrom the target object so that the target object is large as possiblebut still is imaged within a perimeter of the target area. When theoperator does not desire to use the viewing assembly, the pivotingmember is folded down out of the operator's line of vision and out ofharm's way.

The portable data collection device of the present invention includespistol-grip shaped housing enclosing circuitry of the device. An angledsnout extending from a grip portion of the housing includes an openingthrough which a portion of the illumination assembly and optic assemblyextend. A finger operated trigger is provided on a target facing surfaceof the housing. The trigger is depressed by an operator to actuate theimaging assembly to read a bar code dataform in the target area. A pushbutton actuator extends through an opening of the housing spaced apartfrom the trigger. The push button actuator is located so as to bedepressible by the operator's thumb as the housing is cradled in theoperator's hand. Depressing the push button actuator actuates theimaging assembly to capture an image of the target area. A sliderextends through a slotted opening the in the housing and is operativelyconnected to the focusing module. By changing position of the slider, athickness of an optic through which reflected light passes is alteredand the best focusing position of the optic assembly is correspondinglychanged. In an alternate embodiment of the focusing module, imageanalysis circuitry is provided which analyzes gray scale valuescorresponding to a captured image frame and automatically changes thethickness of the focusing module optic to achieve the image of a targetarea.

The aforementioned and other aspects of the present invention aredescribed in more detail in the detailed description and accompanyingdrawings which follow.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a portable data collection device of thepresent invention with a pivoting member of a viewing assembly in afolded down position;

FIG. 1A is a back elevation view of a portion of a housing of theportable data collection device;

FIG. 2 is a perspective view of the portable data collection device withthe viewing assembly pivoting member in an upright position;

FIG. 3 is a sectional view of a portion of a housing of the portabledata collection device with the viewing assembly pivoting member in thefolded down position;

FIG. 4 is a sectional view of a portion of the housing of the portabledata collection device with the viewing assembly pivoting member in theupright position;

FIG. 5 is a view, partly in side elevation and partly in section, of theportable data collection device showing use of the viewing assembly toalign the device with a target object;

FIG. 6 is a top plan view of the portable data collection device;

FIG. 7 is a front elevation view of the portable data collection deviceas seen from a plane indicated by the line 7—7 in FIG. 6;

FIG. 8 is a perspective view of a modular portion of an imaging assemblyof the portable data collection device of the present invention, themodular portion shown imaging a target dataform on an item;

FIG. 9 is a view of the modular portion of the imaging assembly of FIG.8 with an upper half of a housing of the modular portion removed;

FIG. 10 is a schematic sectional view of an optic assembly of themodular portion of the imaging assembly of FIG. 8 including a focusingassembly;

FIG. 11 is an exploded perspective view of an illumination assembly ofthe modular portion of the imaging assembly of the present invention;

FIG. 12 is a perspective view of a lens array or front panel of theillumination assembly of FIG. 11;

FIG. 13 is an exploded perspective view of a targeting optics of thefront panel of FIG. 12;

FIG. 14 is a front elevation view of the front panel of FIG. 12;

FIG. 15 is a back elevation view of the front panel of FIG. 12;

FIG. 16 is a sectional view of the front panel of FIG. 12 as seen from aplane indicated by the line 16—16 in FIG. 14;

FIG. 17 is a sectional view of the front panel of FIG. 12 as seen from aplane indicated by the line 17—17 in FIG. 14;

FIG. 18 is a sectional view of the front panel of FIG. 12 as seen from aplane indicated by the line 18—18 in FIG. 14;

FIG. 19 is an exploded perspective view of an alternate embodiment of anillumination assembly of the modular portion of the imaging assembly ofthe present invention;

FIG. 20 is a perspective view of a lens array or front panel of theillumination assembly of FIG. 19;

FIG. 21 is an exploded perspective view of a targeting optics of thefront panel of FIG. 20;

FIG. 22 is a front elevation view of the front panel of FIG. 20;

FIG. 23 is a back elevation view of the front panel of FIG. 20;

FIG. 24 is a sectional view of the front panel of FIG. 20 as seen from aplane indicated by the line 24—24 in FIG. 22;

FIG. 25 is a sectional view of the front panel of FIG. 20 as seen from aplane indicated by the line 25—25 in FIG. 22;

FIG. 25A is an exploded section view of a portion of the front panelshown in FIG. 25 as seen from a plane indicated by the line 25A—25A inFIG. 22;

FIG. 26 is a sectional view of the front panel of FIG. 20 as seen from aplane indicated by the line 26—26 in FIG. 22;

FIG. 27 is a representation of a crosshair illumination patterngenerated by the illumination assembly of FIG. 11 superimposed on atarget object;

FIG. 28 is a representation of a separation of crosshair illuminationpatterns of two targeting optics of the illumination assembly of FIG. 11caused by imaging with the portable data collection device at a distancefrom a target object significantly different than a best focus positionor distance of an optic assembly of the device;

FIG. 29 is a representation of an angular shift of crosshairillumination patterns of two targeting optics of the illuminationassembly of FIG. 11 caused by imaging with the portable data collectiondevice tilted such that the front panel is not substantially parallel toa surface of a target object;

FIG. 30 is a representation of a crosshair and half frame illuminationpattern generated by a first targeting optics of the illuminationassembly of FIG. 19;

FIG. 31 is a representation of a crosshair and half frame illuminationpattern generated by a second targeting optics of the illuminationassembly of FIG. 19;

FIG. 32 is a representation of a crosshair and full frame illuminationpattern generated by the first and second targeting optics of theillumination assembly of FIG. 19;

FIG. 33 is a representation of a matrix dataform and an associatedsignature block;

FIG. 34A is one portion of a block diagram of selected circuitry of theportable data collection device of the present invention;

FIG. 34B is a second portion of a block diagram of selected circuitry ofthe portable data collection device of the present invention, the secondportion matching the first portion shown in FIG. 34A;

FIG. 35 is a flow chart setting forth one operating embodiment of theportable data collection device of the present invention to decode a barcode dataform and capture an image of a target area;

FIG. 36 is a flow chart setting forth a second operating embodiment ofthe portable data collection device of the present invention to decode abar code dataform and capture an image of a target area;

FIG. 37 is a flowchart setting forth a third operating embodiment of theportable data collection device of the present invention wherein acaptured image frame includes a dataform and a signature block as shownin FIG. 16 and in which decoded dataform data and a portion of thecapture image are output;

FIG. 38 is a perspective view of a support fixture for the focusingassembly of the optic assembly of FIG. 10;

FIG. 39 is a sectional view of the focusing assembly support fixture ofFIG. 38;

FIG. 40 is front elevation view of a movable wedge shaped optic of thefocusing assembly of the optic assembly of FIG. 10;

FIG. 41 is top plan view of the movable wedge shaped optic of FIG. 40 asseen from the plane indicated by the line 41—41 in FIG. 40;

FIG. 42 is a schematic sectional view of an optic assembly of themodular portion of the imaging assembly of FIG. 8 including an alternateembodiment of a focusing assembly;

FIG. 42A is a side elevation view of a portion the focusing assembly ofFIG. 42 as seen from a plane indicated by the line 42A—42A in FIG. 42;

FIG. 43 is a schematic sectional view of an optic assembly of themodular portion of the imaging assembly of FIG. 8 including anotheralternate embodiment of a focusing assembly;

FIG. 44A is one portion of a block diagram of selected circuitry of theportable data collection device of the present invention including thefocusing assembly shown in FIG. 43; and

FIG. 44B is a second portion of a block diagram of selected circuitry ofthe portable data collection device of the present invention, the secondportion matching the first portion shown in FIG. 44A.

DETAILED DESCRIPTION

Turning to the drawings, a portable data collection device in accordancewith the present invention is shown at 10 in FIGS. 1-7. The datacollection device 10 includes a housing 12 defining an interior region.The housing 12 includes a gripping portion 14 sized to be grasped in thehand of an operator and an angled snout 16 extending from the grippingportion. With specific reference to FIG. 7, the snout 16 includes anopening through which a portion of a two dimensional (2D) photosensorarray imaging assembly 18 extends. The imaging assembly 18 includes amodular portion 20 and a control and decoder board 22 electricallycoupled to the electronic circuitry in the modular portion. The controland decoder board 22 is supported within the gripping portion 14 of thehousing 12. Also supported within the housing gripping portion 14 is apower source 24 such as a rechargeable battery for supplying operatingpower to the portable data collection device 10.

A dataform reading trigger switch or actuator 26 extends through anopening in the gripping portion 14. Also extending through an opening inthe gripping portion 14 is an imaging push button trigger switch oractuator 28. The dataform reading trigger 26 is positioned to bedepressed by an index finger of the operator while the gripping portion14 of the housing 12 is held in the operator's hand. The imaging trigger28 is positioned to be depressed by a thumb of an operator while thegripping portion 14 of the housing 12 is held in the operator's hand.Also extending through an opening in the housing 12 just above theimaging trigger 28 is a slider 29 moveable along a path of traveldefined by a slotted opening 29 a in the gripping portion 14. As will bediscussed below, moving the slider 29 causes a best focus position ordistance of an optic assembly 43 of the imaging assembly 18 to changethereby allowing the operator to change a focusing range of the dataformreader 10. The slider 29 is positioned on the housing snout 16 to permitoperation by the operator's thumb. Moving the slider 29 to an end 29 b(FIG. 1A) of the slotted opening 29 a causes the optic assembly 43 tohave a best focus distance at approximately 5.5 inches (140 mm.) infront of an outwardly facing surface 90 of a forwardmost lens of theoptic assembly 43. On the other hand, moving the slider 29 to anopposite end 29 c of the slotted opening 29 a causes the optic assembly43 to have a best focus distance at approximately 36 inches (915 mm.) infront of the outer surface 90 of the forwardmost lens of the opticassembly 43.

The gripping portion 14 also includes two small openings through which adistal portion of a red light emitting diode (LED) indicator 30 and adistal portion of a green LED indicator 32 extend. Finally, the housing12 includes an opening exposing a portion of a microphone 34 mounted inthe housing interior region and another opening through which a radioantenna 36 extends. The interior region of the housing 12 supports theimaging assembly 18 and other electronic circuitry to be describedbelow.

Referring to FIG. 8, which shows a perspective view of the modularportion 20 of the imaging assembly 18, it can be seen that the modularportion includes a housing 40 which supports an illumination assembly 42and a board camera assembly 38. The housing 40 includes an upper portion39 a and a lower portion 39 b which advantageously are identicallyshaped and positioned symmetrically about a part line 41. The boardcamera assembly 38 includes the optic assembly 43 which focuses an imageof a target area 44 onto a photosensor array 48. The target area 44 isdefined by a field of view of the board camera assembly 38. The targetarea 44 will generally include a target object 45 such as a one or twodimensional bar code dataform or a matrix dataform to be decoded. Theillumination assembly 42 includes four illumination optic portions 88 a,88 b, 88 c, 88 d each of which projects an even intensity distributionof illumination across the target area 44.

FIG. 9 is a top view of the modular portion 20 with the upper portion 39a of the housing 40 removed. The board camera assembly 38 includes arear printed circuit board 52 and a front printed circuit board 54, bothof which are secured in the housing 40 in slots 56 a, 56 b, 56 c, 56 d.A two dimensional photosensor array 48 is positioned on a support 49(FIG. 10) affixed to a front surface 54 a of the front printed circuitboard 54. The photosensor array 48 receives reflected illumination fromthe target area 44 focused through an optic assembly 43. The support 49surrounds the photosensor array 48 and holds a thin piece of quartz 50in spaced apart, parallel relationship with wht photosensor array 48.The quartz piece 50 has a thickness of 0.6 mm. and is spaced 1.310 mm.from the photosensor array 48. The quartz piece 50 has an index ofrefraction of 1.5443.

A shroud 58 positions the optic assembly 43 with respect to thephotosensor array 48 and shrouds ambient illumination from the array.The illumination assembly 42 includes a printed circuit board 60, a lensarray 62 and two targeting LEDs 64 a, 64 b. The lens array 62 functionsas the outer or front panel of the modular portion 20. The term “frontpanel” will be used interchangeably with the term “lens array”throughout. A plurality of exposure LEDs 66 are disposed on the frontsurface of the printed circuit board 60 to direct illumination throughthe front panel 62 towards the target area 44. The circuit board 60 andthe front panel 62 are secured in slots 56 e, 56 f, 56 g, 56 h in theupper and lower housing portion 39 a, 39 b. Securing the board cameraassembly 38 and the illumination assembly 42 in the same housing 40assures that illumination is properly directed onto the target area 44.

FIG. 10 shows a cross section of the camera assembly 38 with the opticassembly 43 focusing an image of the target area 44 including an imageof the target object 45 onto the photosensor array 48. The performanceof the portable data collection device 10 is enhanced by the opticassembly 43 including a focusing assembly 800 which provides the boardcamera assembly 38 with an extended, variable working range. Thefocusing assembly 800 is operable to vary a best focus position ordistance S2 (FIG. 10) of the optic assembly 43. The best focus positionS2 is a distance from an outermost optic surface 90 of a forwardmostlens 43 a of the optic assembly 43 to the target object 45 at which thebest or clearest image of the target object is focused on thephotosensor array 48. The sharpness of the focused image graduallydegrades as the target object 45 is moved from the best focus positionS2 towards a near field cut off distance S1. If the target object 45 isa dataform, moving the target object 45 closer than the near field cutoff distance S1 would result in an image projected onto the photosensorarray 48 that is undecodable. Similarly, the image sharpness graduallydegrades as the target object 45 is moved from the best focus positionS2 towards a far field cut off distance S3. Assuming that the targetobject 45 is a dataform, moving the target object 45 further away thanthe far field cut off distance S1 would result in an image projectedonto the photosensor array 48 that is undecodable.

The focusing module 800 includes a focusing optic 810 comprising twowedge shaped lens 820, 830 which are congruent in shape and supported ina lens support fixture 840 (seen in FIGS. 38 and 39). As can best beseen in FIGS. 10, 39 and 41, the lens 820, 830, when viewed from above,define congruent triangles. The angles labeled “a” in the lens 820, 830are both substantially 90 degree angles and the acute angle labeled “b”in lens 820 is substantially equal to the acute angle labeled “b” inlens 830. The lens 820, 830 are supported by the fixture 840 such thatthe flat, inclined surfaces 822, 832 of lens 820, 830 are parallel andadjacent. Further, outwardly facing flat surfaces 824, 834 aresubstantially parallel. The focusing optic 810 is positioned such thatit is substantially perpendicular to a central ray c (FIG. 10) ofreflected light from the target area 44 which passes through lens 43 a,43 b, 43 c, 43 d, 43 e of the optic assembly 43. The lens 820, 830 arepreferably fabricated from type BK7 glass having a refractive index of1.5168. Type BK7 glass is available from Schott Glass Technologies, Inc.of Duryea, Pa.

The focusing module 800 is configured such that an effective thickness tFIG. 10) of the focusing optic 810 through which the reflected lightpasses may be changed by the operator of the portable data collectiondevice 10 to vary the best focus position S2 of the optic assembly 43.Correspondingly, the near field cut off distance S1 and the far fieldcut off distance S2 will also be changed as follows:

Thickness Best Focus Distance Near Field Cutoff Far Field Cutoff t S2 S1S3  1.0 mm. 140 mm. (5.5 in.)  65 mm. (2.5 in.) 290 mm. (11.5 in.) 1.726mm. 305 mm. (12.0 in.)  90 mm. (3.5 in.) 600 mm. (23.5 in.) 2.136 mm.915 mm. (36.0 in.) 150 mm. (6.0 in.) Infinity

The minimum value of S2 (5.5 in. or 140 mm.) will be referred to as MINS2.

Suitable dimensions for the two lens 820, 830 comprising the focusingoptic 810 are as follows:

Lens Description & Label Dimension 820 Height A (FIG. 41) 10.00 mm.  820Base B (FIG. 41) 2.25 mm. 820 Width E (FIG. 40) 4.00 mm. 830 Height C(FIG. 41) 4.00 mm. 830 Base D (FIG. 41) 0.90 mm. 830 Width E (FIG. 40)4.00 mm.

The distance labeled D1 corresponds to a distance between an opticsurface 110 of the rearwardmost lens 43 e and the forward facing surface824 of the lens 820. A suitable distance D1 is 3.1209 mm. The distancelabeled D2 corresponds to a distance between the rearward facing surface834 of the lens 830 and the photosensor array 48. A suitable distance D2is 4.4000 mm. The total distance DT between the photosensor array 48 andthe optic surface 110 of the rearwardmost lens 43 e the sum of D1, D2and focusing optic thickness t, $\begin{matrix}{{DT} = {{D1} + {D2} + t}} \\{= {3.1209\quad {{mm}.{+ 4.4000}}\quad {{mm}.{+ 1.00}}\quad {{mm}.}}} \\{= {8.5209\quad {{mm}.}}}\end{matrix}$

Operationally, the thickness t of the focusing optic 810 is varied bymoving or sliding the lens 820 with respect to the lens 820. As can bestbe seen in FIGS. 40 and 41, the moveable lens 820 includes a pair ofprojecting flanges 825, 826 extending from top and bottom surfaces 827,828 of the lens 820. The projecting flanges 825, 827 slidingly engagerespective slots 842, 844 of spaced apart horizontal plates 846, 848 ofthe support fixture 840. The slots 842, 844 function to guide theprojecting flanges 825, 827 and, therefore, the moveable lens 820 alonga path of travel labeled T in FIG. 39.

A drive means 850 is provided to move the moveable lens 820 along thepath of travel T. The drive means 850 includes a flexible belt 852having one end 854 attached to a base surface 829 of the lens 820. Anopposite end 856 of the belt 852 is attached to the slider 29. A portion29 d of the slider 29 extends through the slotted opening 29 a in anoperator facing back side of the snout 14 of the housing 12. The slider29 is slidably confined between a pair of parallel ledges 29 e, 29 f(which can be seen in dashed line in FIG. 1A and one of which can beseen in FIG. 10) which extend outwardly from the inner surface 16 a ofthe housing snout 16. The ledges 29 e, 29 f have peripheral lips 29 g tofurther confine the slider 29. As the slider portion 986 is moved alongthe slotted opening 988 in a direction labeled R in FIG. 10, the belt852 moves in the same direction and the lens 820 correspondingly moves.As can be seen in FIG. 10, the belt 852 is supported by guides 858, 860extending from an inner surface of the housing snout 16. The belt 852extends through a guide 862 defining an opening in the modular housing20 and another guide 864 defining an opening in the shroud 58. The belt852 further extends through a guide 866 in a vertical side plate 868 ofthe fixture 840. The fixture includes the vertical side plate 868 andanother vertical side plate 870 which function to maintain the properspaced relation between the horizontal plates 846, 848. The fixture 840is secured to the front side 54 a of circuit board 54 by four screws 872extending through openings in flanges 874 and through the circuit board54. The flanges 874 extend from the horizontal plates 846, 848.

The belt 852 is flexible enough the conform to the curves defined by theguides 858, 860 but is stiff enough to move the moveable lens 820 alongits path of travel T when the slider 29 is moved along the slottedopening 29 a. When the slider 29 is moved, lens 820 moves along its pathof travel T guided by the engagement of the projecting flanges 825, 827and the slots 842, 844 of spaced apart horizontal plates 846, 848. Asthe moveable lens 820 moves the moveable optic contact surface 822slides across the stationary optic contact surface 832 thereby varyingthe thickness t of focusing optic 810, that is, varying the totaldistance the reflected light from the target area 44 must traversebefore reaching the photosensor array 48.

The stationary lens 830 can be thought of as a compensation lens becauseit causes the focusing optic 810 to have a shape of a plate of glasswith two parallel faces oriented such that the faces are normal orperpendicular to the incident reflected light no matter what theposition of the moveable lens 820. Different positions of the moveablelens 820 are shown in FIG. 10. In solid line, a position of the lens 820at one end of its path of travel T is shown. This position correspondsto a minimum thickness t of the focusing optic 810. In the dashed linelabeled 820 a, an intermediate position of the lens 820 is showncorresponding to a medium thickness t of the focusing optic 810.Finally, in the dashed line label 820 b, a position of the lens 820 atan opposite end of its path of travel T is shown. This positioncorresponds to a maximum thickness t of the focusing optic 810. When theslider 29 is in the position shown in FIG. 10, that is, abutting the end29 b of the opening 29 a, the moveable lens 820 is at the position whichresults in a minimum thickness t of the focusing optic 810. As theslider 29 is moved to a position abutting the opposite end 29 c of theopening 29 a, the moveable lens 820 is at the position labeled 820 bwhich results in a maximum thickness t of the focusing optic 810.

By using the two wedge shaped lens 820, 830 as shown, the resulatantfocusing optic 810 is equivalent to a glass plate with parallel sidesand variable thickness. Since the index of refraction of the focusingoptic 810 (1.5168) is greater than the index of refraction of air,inserting the optic 810 between the innermost lens 43 e of the opticassembly 43 and the photosensor array 48 will change the best focusdistance S2. As the thickness of the focusing optic 810 increases, thebest focus distance S2 also increases. Thus, imprinted on the housingsnout 16 adjacent the end 29 b of the opening 29 a is the letter “N”indicating to the operator that moving the slider 29 toward the end 29 bwill cause the optic assembly 43 reduce its best focus distance S2. Theopposite end 29 c has a letter “F” imprinted near it to indicate thatmoving the slider toward the end 29 c will increase the best focusdistance S2. Since the focusing optic 810 is essentially a glass platewith parallel sides, the reflected light passing through the optic 810is not subject to image shift or tilt.

When the focusing optic 810 has it minimum thickness t of 1.0 mm., thebest focus position MIN S2 is at 140 mm. (5.5 in.) from the outwardfacing optic surface 90 of the lens 43 a. At the best focus position of140 mm., the field of view or target area 44 of the optic assembly 43 isgenerally rectangular in shape and having dimensions of approximately 82mm. (3.2 in.) long by 62 mm. (2.4 in.) high. At a distance of 8.5 inchesfrom the front surface 90, the target area of the optic assembly 43 isapproximately 127 mm. (5 inches) long by 95 mm. (3.75 inches) high. Theoptic assembly 43 is capable of decoding a bar code dataform with narrowwidth bars (e.g., a bar code dataform with a minimum bar width of 0.015in. (0.381 mm.) at the near field distance S1).

The preferred optic assembly 43 includes the five lens 43 a, 43 b, 43 c,43 d, 43 e and a metal disk 98 having a pin hole aperture 98 a which, asshown, includes eleven optic surfaces labeled 90-110. In the preferredembodiment the rear most optic surface 110 of lens 43 e is positioned10.2 mm. to the front of the photosensor array 48, that is, the distancelabeled DT in FIG. 10 is 10.2 mm.

The optic prescriptions for each of the optic surfaces are as follows:

Radius of Optic Surface Surface Curvature Diameter Shape 90 R = 13.52mm. D = 8.8 mm. convex 92 R = 5.3 mm. D = 8.8 mm. concave 94 R = 12.47mm. D = 7 mm. convex 96 R = 19.9 mm. D = 7 mm. convex 98 Pinholediameter 0.81 mm. 100 R = 6.76 mm. D = 7 mm. concave 102 R = 12.47 mm. D= 7 mm. concave 104 R = 158.52 mm. D = 7 mm. convex 106 R = 6.76 mm. D =7 mm. convex 108 R = 28.08 mm. D = 7 mm. convex 110 R = 11.26 mm. D = 7mm. convex

The distance between successive optical surfaces 90-110 is as follows:

Optic Surface Distance 90-92 0.77 mm. 92-94 4.632 mm. 94-96 2.32 mm.96-98 1.798 mm.  98-100 0.805 mm. 100-102 0.77 mm. 102-104 0.327 mm.104-106 2.34 mm. 106-108 0.178 mm. 108-110 2.07 mm.

Such an optic assembly is available from Marshall Electronics, Inc. ofCulver City, Calif.

An alternate optic assembly which includes a compact aspheric plasticdoublette design can be found in U.S. patent application Ser. No.08/494,435, filed Jun. 26, 1995, entitled “Extended Working RangeDataform Reader”, now issued as U.S. Pat. No. 5,811,784 on Sep. 22,1998. U.S. Pat. No. 5,811,784 is incorporated in its entirety herein byreference.

Because the desired working range and field of view of the portable datacollection device 10 dictates that the optic assembly 43 have a large F#(F#5.6 or greater), the illumination assembly 42 must provide adequateillumination of the target area 44 during the exposure period so thatenough reflected light is absorbed by the photosensor array 48 togenerate a suitably bright image. However, the exposure period isnormally limited to 0.01 seconds or less to minimize the smear effect ofan operator's hand jittering during a dataform reading session.Therefore, the illumination assembly 42 must provide adequateillumination to accommodate the large F# and short exposure time.

Proper exposure of the photosensor array 48 requires an object fieldillumination of 0.3 lux assuming an exposure period of 0.03 seconds andan F#1.2. To determine the proper object field illumination for a 0.01second exposure period and an F#13, the following formula is used:$\frac{\left( {{Illumination}\quad {intensity}} \right)\left( {{Exposure}\quad {period}} \right)}{\left( {F\#} \right)^{2}} = {Constant}$

Therefore, the minimum required object field illumination for thisinvention is 106 lux at the far field cut off distance S3.

Referring to FIG. 11, which is an exploded perspective view of theillumination assembly 42, the printed circuit board assembly 60 includesa plurality of surface mount exposure illumination LEDs 66. An acrylicor polycarbonate lens array 62 is positioned between the printed circuitboard assembly 60 and the target area 44 for directing the illuminationfrom the exposure LEDs 66 towards the target area 44. Preferably, thelens array 62 is a unitary structure fabricated from the material PMMA(polymethyl methacrylate). However, it should be appreciated that itcould be fabricated from other suitable materials such as glass or acombination of glass optics supported in a molded panel or othersuitable arrangement known to those skilled in the art. The printedcircuit board assembly 60 includes printed conductors and a power lead112 operative for supplying power to the illumination LEDs 66. Asuitable surface mount illumination LED is produced by the MarkTechCorporation of Latham, N.Y., as Part No. MTSM735K-UR or MTSM745KA-UR.Each illumination LED 66 provides illuminosity of 285 milli candela(mcd) over an angular illumination field of about 68 degrees. The smallfootprint of each illumination LED 66 enables four LEDs to be placed ina row measuring less than 14 mm. The printed circuit board assembly 60includes four banks of four illumination LEDs 66 totaling sixteenillumination LEDs providing 4560 mcd of uniform illumination over thetarget area 44.

The lens array 62 includes four illumination optic portions 88 a, 88 b,88 c, 88 d each of which are aligned with a corresponding bank ofillumination LEDs 66. The illumination optic portions 88 a, 88 b, 88 c,88 d direct a 68 degree angular illumination field from eachillumination LED 66 into a uniform field having an angular field of viewwhich substantially corresponds to the angular field of view of theoptic assembly 43 which defines the target area 44 (shown in FIGS. 8 and9).

Referring to FIGS. 16 and 18, which show a horizontal cross section(FIG. 16) and a vertical cross section (FIG. 18) through theillumination optic portions 88 a, 88 b, 88 c, 88 d, it can be seen thateach optic portion includes four vertically oriented cylindrical entrysurfaces 116, one positioned in front of each LED 66 and a horizontallyoriented cylindrical exit surface 118 positioned in front of each bankof LEDs 66. The vertically oriented cylindrical entry surfaces 116define the horizontal field of illumination and the horizontallyoriented cylinders 118 define the vertical field of illumination. Thisarrangement provides an even illumination intensity distribution acrossthe target area 44. The 4560 mcd of illumination provided by theillumination LEDs 66 will provide an illumination intensity in excess of106 lux at a distance of 8.5 inches from the outermost optic surface 90of the optic assembly lens 43 a.

A central opening 67 in the printed circuit board assembly 60 providesan opening for the shroud 58 to extend through. The vertically orientedentry surfaces 716 have a radius of curvature of 2.50 mm. and a height I(FIG. 35) of 4.00 mm while the horizontally oriented exit surfaces 718have a radius of curvature of 3.00 mm. and a width J (FIG. 36) of 13.75mm. Referring to FIGS. 34-36, suitable dimensions for the lens array 702are as follows:

Label Description Dimension A Height of lens array 62 21.75 mm. B Widthof lens array 62 39.55 mm. C Diameter of center opening 12.00 mm 67 oflens array 62 D Height between middle of vertical entry surfaces 11614.13 mm. E Thickness of lens array 62  1.95 mm.

Referring again to FIG. 11, the illumination assembly 42 also includes atargeting arrangement or assembly 64 to aid in aiming the device 10 atthe target object 45. The targeting assembly includes the targeting LEDilluminators 64 a, 64 b, which, when energized, project illuminationthrough apertures 68, 70 in the printed circuit board 60 and into firstand second targeting optics 72, 74 respectively of the lens array 62.The first and second targeting optics 72, 74 are mirror images of eachother and are identical in configuration. Each targeting optic generatesa crosshair pattern of illumination CR1, CR2 (seen in FIG. 27) and, aswill be discussed below, if the target object 45 is at a proper distancefor imaging, i.e., at the minimum best focus position MIN S2 of theoptic assembly 43, the crosshairs CR1, CR2 will coincide or overlapproducing a single rectangular crossing or crosshair pattern ofillumination CR (FIGS. 11 and 27). The rectangular illumination patternCR will have a height h (18 mm.) and a width w (18 mm.) (FIG. 11). Ofcourse, the rectangular illumination pattern CR will not be a perfectintersecting line crosshair but rather will be characterized by anillumination intensity distribution or pattern having some visible“thickness” t (FIG. 11) but will nonetheless be suitable for aiming thedevice 10.

The first and second targeting optics 72, 74, which are identical inconfiguration, are shown in cross section in FIGS. 17 and 18. The firsttargeting optics 72 comprises a lens with an aspherical light entryoptic surface 726 and a segmented cylindrical light exit optic surface728. The second targeting optics 74 comprises a lens with an asphericallight entry optic surface 730, similar to the aspherical light entryoptic surface 726, and a segmented cylindrical light exit optic surface732, similar to the segmented cylindrical light exit optic surface 728.

The aspherical entry surfaces 726, 730 each have a diameter of 8 mm., aradius of curvature of 2.890 mm. and a conic constant of −2.534. Thesegmented cylindrical light exit surfaces 728, 732 each have an 8.0 mm.by 8.0 mm. square shaped outer perimeter. The segmented cylindricalsurface 728 is comprised of four triangular shaped sections 740, 742,744, 746 (FIG. 14) while the segmented cylindrical surface 732 isdivided into four triangular shaped sections 750, 752, 754, 756, whereinthe optic surfaces of sections 740 and 750 are identical, the opticsurfaces of sections 742 and 752 are identical, the optic surfaces ofsections 744 and 754 are identical and the optic surfaces of sections746 and 756 are identical.

Upper and lower triangular sections 740, 744 comprise verticallyoriented cylindrical light exit optic surfaces. Left and righttriangular sections 742, 746 comprise horizontally oriented cylindricallight exit optic surfaces. Similarly, upper and lower triangularsections 750, 754 comprise vertically oriented cylindrical light exitoptic surfaces, while left and right triangular sections 752, 756comprise horizontally oriented cylindrical light exit optic surfaces.The vertically oriented cylindrical optic surfaces 740, 744, 750, 754have a radius of curvature of 25.00 mm. Similarly, the horizontallyoriented cylindrical optic surfaces have a radius of curvature of 25.00mm.

As can best be seen in FIG. 17, the horizontally and vertically orientedcylindrical optic surfaces 742, 746, 740, 744 are tipped at an angle cwith respect to a longitudinal axis L—L though the lens array 62 and,therefore, is also tipped at an angle c with respect to the target area44. The tip angle c of the horizontally oriented cylindrical opticsurfaces 742, 746 shifts the horizontal position of the illuminationrectangle or targeting crosshair CR1 (seen in FIG. 28) generated by thefirst targeting optics 72 such that it is horizontally centered in thetarget area 44 while the tip angle c of the vertically orientedcylindrical optic surfaces 740, 744 shifts the vertical position of thetargeting crosshair CR1 generated by the first targeting optics 72 suchthat it is vertically centered in the target area 44. A suitable tipangle of c is 9.85 degrees.

Similarly, as can also be seen in FIG. 17, the horizontally andvertically oriented cylindrical optic surfaces 752, 756, 750, 754 arealso tipped at an angle c which is preferably 9.85 degrees with respectto a longitudinal axis L—L though the lens array 62. Note that thedirection of tilt of the segmented cylindrical light exit surfaces 728,732 are the same in magnitude but opposite in a direction of tilt, thatis, the light exit surface 728 of the first targeting optics 72 slantsdownwardly to the left toward the front side 719 in FIG. 17, while thelight exit surface 732 of the second targeting optics 74 slantsdownwardly to the right toward the front side 719 in FIG. 17. Also notethat the two horizontally oriented light exit optic surfaces 718 whichwould be seen in FIG. 17 (and in FIG. 25 discussed below with respect toan alternate embodiment of the illumination assembly 42) have beenremoved for clarity of the drawing. It should also be noted that FIG. 13which shows the segmented cylindrical light exit surface 732 as beingcomprised of four individual exploded “pieces” is only a representationto provide additional clarity as to the shape and tilt of the four lightexiting surfaces 750, 752, 754, 756. The lens array 62 is fabricated asa single piece and the targeting optics 72, 74 and illumination optics116, 118 are formed in the single piece. The lens optics are notfabricated by “piecing” together individual optics. The same is truewith respect to the optic “pieces” represented in FIG. 21 of thealternate embodiment of the illumination assembly 42 shown in FIGS.19-26 to be discussed below.

Additional suitable dimensions, labeled on FIG. 17, for the asphericlight entry surfaces 726, 730, the segmented cylindrical light exitsurfaces 728, 732 of the lens array 62 are as follows:

Label Description Dimension F Maximum extension of aspheric 1.75 mm.light exit surfaces 726, 730 from back side 717 of lens array 62 GDistance between maximum extension 5.25 mm. of aspheric light exitsurfaces 726, 730 and center of respective segmented light exit surfaces728, 732 along centerlines T-T H Distance between centerlines T-T 7.80mm. and outer edge of lens array 62

As noted above, the minimum best focus distance MIN S2 is 140 mm. (5.5inches). If the device 10 is oriented such that the lens array 72 issubstantially parallel to a surface of the target object 45 (a dataformto be imaged and decoded) and positioned at the minimum best focusdistance MIN S2 from the target object 45, then the targeting crosshairsCR1 and CR2 will coincide and generate the single targeting crosshair CRas shown in FIGS. 11 and 27 having an approximate height h of 18 mm .(0.7 in.) and an approximate width w of 18 mm . (0.7 in.) whichcorresponds to the target area 44 height of 62 mm. (2.4 in.) and a widthof 82 mm. (3.2 in.) at the minimum best focus position MIN S2 of 140 mm.(5.5 inches) in front of the optic surface 90.

If the device 10 is moved away from the minimum best focus distance MINS2 with respect to the target object 45, the targeting crosshairs CR1and CR2 will separate horizontally as shown in FIG. 28 thereby informingthe operator that the distance of the device 10 from the target object45 is not correct for best imaging or imaging and decoding. The operatorwill adjust the focusing optic 810 using the slider 29 appropriately tocompensate for the distance between the target object 35 and the opticassembly 43. For example, if the distance between the target object 45and the optic assembly 43 is more than 36 inches and, if the distancefor some reason cannot be reduces (e.g., because the target object 45 isabove the operator's outstretched arm and hand) the operator would usehis or her thumb to move the slider 29 to the “F” marked end 29 c of theslotted opening 29 a so as to increase the best focus distance S2 fromits minimum value (140 mm. or 5.5 in.) to its maximum value (915 mm. or36.0 in.). Of course, if the operator can move the device 10 withrespect to the target object 45, the preferred mode of operation wouldbe to have the slider 29 at the “N” marked end 29 b of the slottedopening 29 a and adjust the device's distance from the target object 45such that the CR1 and CR2 crosshairs overlap. At that point, the targetobject distance will be 140 mm. (5.5 in.) and corresponding to the opticassembly 43 minimum best focus distance MIN S2 140 mm. (5.5 in.).

Finally, if the lens array 702 is not substantially parallel to asurface of the target object 45, that is, the device 10 is tiltedforward or backward from a position where a front surface 719 (FIGS. 12and 17) of the lens array or front panel 72 is parallel to the targetobject surface, the vertical portions of the illumination patterns ofCR1 and CR2 will be angularly shifted or displaced as shown in FIG. 49,the greater the angle of tilt of the device 10, the greater will be theangular shifting of the vertical portions of the illumination patternsCR1, CR2.

Referring again to FIGS. 1-4, the portable data collection device 10also includes a viewing assembly 600. The viewing assembly 600 includesa pivoting member 602 which pivots between a folded down position (FIGS.1 and 3) and an upright position (FIGS. 2 and 4). The pivoting member602 includes a rectangular opening 604. The opening 604 is approximately32 mm. in the horizontal direction, labeled 606 in FIG. 2, and isapproximately 24 mm. in the vertical direction, labeled 608 in FIG. 2.The horizontal and vertical dimensions 606, 608 of the opening 604 arechosen such that an angle of divergence or field of view of an operator605 looking through the opening 604 at a distance of approximately 56mm, labeled ED in FIG. 5, is substantially the same as the field of viewof the imaging assembly 18. The ratio of the horizontal dimension 606 tothe vertical dimension 609 is chosen to correspond to the ratio of thehorizontal dimension to the vertical dimension of the matrix ofphotosensors comprising the 2D photosensor array 48.

As can be seen in FIG. 5, when in an upright position, the pivotingmember 602 is in a line of vision of the operator 605. When the opening604 is position approximately 56 mm. from the operator's eye, a viewingarea 610 through the aperture 604 substantially corresponds to thetarget area 44 of the imaging assembly 18.

The pivoting member 602, when in the folded down position, is receivedin a well or recessed area 608 defined by an upper surface of thehousing snout 16. In the folded down position, an upper surface 612(FIG. 3) of the pivoting member 602 is substantially flush with thesnout upper surface. The snout upper surface 610 includes a recessedportion 614 (FIGS. 1 and 2) sized to permit an operator's finger tip toslip under a front lip 616 of the pivoting member 602 to permit themember to be popped up to the upright position from the folded downposition. As can best be seen in FIGS. 3 and 4, the pivoting memberfront lip 616 member 602 fits under a slightly extending upper edge 617of the snout upper surface to hold the pivoting member with a slightinterference fit in the folded down position.

The pivoting member 602 pivots on a pair of cylindrical portions 618which extend from sides of the pivoting member near its bottom edge. Thecylindrical portions 618 rotatably fit within corresponding cylindricalrecesses in the snout 16. Turning to FIGS. 3 and 4, an arcuate biasingspring 620 positioned in a recessed portion 622 of the snout 16. Therecessed portion 622 is shaped to confine the spring 620 with edgeportions of the snout defining the recessed portion. The spring 620 hasa humped middle portion which biases the pivoting member 602 to eitherthe upright position or the folded down position.

In the preferred embodiment of the portable data collection device ofthe present invention, the photosensor array 48 is part of the boardcamera assembly 38 commercially available from such vendors as Sharp orSony of Japan. Referring to FIGS. 17A and 17B, the camera assembly, whenactivated, generates a composite video signal 262. The board cameraassembly 38 also includes a clock generator 256, synchronization signalcircuitry 258 and analog signal processing circuitry 260 for readingillumination intensity values out of each photosensor of the photosensorarray 48 and generating the composite video signal 262.

The intensity of light incident on individual pixels or photosensors ofthe photosensor array 48 varies somewhat uniformly from very bright(whitest areas of the image) to very dark (darkest areas of the image).The preferred 2D photosensor array 48 comprises an interlaced 752 by 582matrix array of photodiode photosensors or image pixels (for a total of437,664 pixels). The clock generator 256 coupled to a crystal oscillatorand generates asynchronous clocking signals to read out chargesaccumulating on individual photosensors over an exposure period. Thecharges on the photosensors are read out through CCD elements adjacentthe photosensor array photosensors. The charges are converted to avoltage signal 250 wherein temporal portions of the voltage signalrepresent the changes accumulated on each photosensor. One CCD elementis provided for reading out the charges on two photosensors thus tworead outs of the photosensor array comprise one full image frame, theframe being comprised of two interlaced fields.

The camera assembly 38 generates the composite analog video signal 262(FIG. 17A) corresponding to consecutive fields of the image incident onthe photosensor array 48. The video signal 262 is termed “composite”because it includes synchronization signals generated by thesynchronization signal circuitry 258 which correlate portions of thevideo signal to particular photosensors, interspersed among image signalportions wherein the signal magnitude represents charges on individualphotosensors read out from a given row of the photosensor array 48.

The board camera assembly 38 also includes gain control circuitry 252for controlling amplification of the image signal 253 and exposureperiod control circuitry 254 for controlling a duration of an exposureperiod of the pixels. Both the exposure period control circuitry 254 andthe gain control circuitry 252 are controlled by fuzzy logic exposureparameter control circuitry discussed with reference to FIG. 34A.

The synchronization signals 268 generated by synchronization signalcircuitry 258, the clock signal 270, generated by the clock generator256, and the composite video signal 253 are output to signal processingcircuitry 264 on the control and decoder board 22. Because the signalprocessing circuitry is configured to receive a composite video signal,it should be appreciated that selection of the board camera assembly 38and its accompanying components for generating the composite videosignal are not critical to the present invention.

Under the control of a microprocessor 266 mounted on the control anddecoder board 22, the video signal 262 is input to the signal processingcircuitry 264 along with clocking signals 268 and synchronizationsignals 270. The signal processing circuitry 264 includessynchronization extractor circuitry which receives the clocking signals268 and the synchronization signals 270 and generates signals which arecoupled to analog to digital converter circuitry (A/D convertercircuitry) 272 causing the A/D converter circuitry to periodicallydigitize the video signal 262. The A/D converter circuitry 272 includesan A/D converter generating an 8 bit value representing the illuminationincident on a pixel of the array.

Direct memory access (DMA) control circuitry 275 receives thesynchronization signals 270 and clock signals 268 and generates addresssignals 276 a coupled to the frame buffer memory 274 to indicate astorage location for each value generated by the A/D converter circuitry272.

Data signals 276 representing the values generated by the A/D convertercircuitry 272 are coupled to the frame buffer memory 274. Control andselection circuitry 284 mounted on the control and decoder board 22 andcoupled to the frame buffer memory 274 receives successive image framestemporarily stored in the frame buffer memory 274. Also coupled to thecontrol and selection circuitry 284 are the dataform read triggercircuit 26 a which, in turn, is coupled to the dataform reading trigger26 and an image capture trigger circuit 28 a which, in turn, is coupledto the imaging trigger 28.

When an operator institutes a dataform reading session (dataform readingmode) by depressing the dataform reading trigger 26, the dataform readtrigger circuit 26 a sends a signal to the control and selectioncircuitry 284 causing the control and selection circuitry to couple acaptured frame from the frame buffer memory 274 to image processing anddecoder circuitry 290.

The image processing and decoding circuitry 290 includes a decoder 292for decoding 1D and 2D dataforms in the target area 44. The imageprocessing and decoder circuitry 290 operates on the stored frame ofimage data to extract dataform cell data (determine the black or whitevalue of each cell of the dataform) and decode the cell data. Cellextraction is done in accordance with U.S. patent application Ser. No.08/543,122 entitled, “Sub Pixel Dataform Reader With Dynamic NoiseMargins”, filed Oct. 13, 1995 now issued as U.S. Pat. No. 5,979,763 onNov. 9, 999, and assigned to the assignee of the present invention. Thecontents of application Ser. No. 08/543,122 are hereby incorporated byreference. Decoding of the cell data is accomplished by known decodingmethods for each particular dataform format.

Also coupled to the control and selection circuitry 284 is imagecompression circuitry 294 and serial output circuitry 296. The controland selection circuitry 284 routes data 298 representing a decodeddataform data directly from the decoding circuitry 292 to the serialoutput circuitry 296. The decoded dataform data 298 is not compressedprior to output to the serial output circuitry 296. There is apossibility of error in the compression and subsequent decompressionprocess and losing even a portion of a decoded dataform data may resultin adverse consequences such as subsequent errors in updating inventory,determining the status or tracking an item, etc. Thus, the decodeddataform data 298 is not compressed.

When an operator institutes an imaging session (imaging mode) bydepressing the imaging trigger 28, the image capture trigger circuit 28a sends a signal to the control and selection circuitry 284 causing theselection circuitry to couple a captured frame from the frame buffermemory 274 to image compression circuitry 294 to be compressed beforebeing output to the serial output circuitry 296 or directly to theserial output circuitry 296 without being compressed.

Generally, the control and selection circuitry 284 will be programmed toroute the data representing a captured image frame to the imagecompression circuitry 294 because the occurrence of one or more errorsin the data representing an image is normally not a significant problem.That is, an image of an item in the target area 44 will still berecognizable and useful to supervisory personnel viewing the imagereconstructed from the captured image frame data even if there is someslight distortion of the image. After compression of the image data bythe image compression circuitry 294, compressed image data 300 is routedto the serial output circuitry 296. If, however, a high resolution imageis needed, the control and selection circuitry 284 may be appropriatelyprogrammed to route the data representing the captured frame directly tothe serial output circuitry 296.

The image compression circuitry 294 utilizes an image compressionalgorithm to reduce the size of a set of digital image data. One suchalgorithm is the 2D wavelet transform compression algorithm as describedin “A 64 Kb/s Video Code Using the 2D Wavelet Transforms” by A. S. Lewisand G. Knowles, published in IEEE Computer Society Press, Order No.2202. The HARC Wavelet Transform System utilizing such technology isavailable from Houston Advance Research Center in Houston, Tex. and iscapable of compressing photographic data with an image compression ratioof up to 400:1.

Because the portable data collection device 10 is adapted for use inremote on-site locations for reading a dataform identifying a particularitem or capturing an image of an item, it is desirable to enable theimaging assembly 18 to also capture a verbal message from the operator.The control and decoder board 22 also includes a voice capture module304 for capturing and digitizing an operator's verbal message and voicecompression circuitry 306 for compressing the captured verbal message.The voice capture module 304 is coupled to the microphone 34 and isoperable by the control and selection circuitry 284 to capture anddigitize audio input. The voice compression circuitry 306 compresses adigitized voice signal. Data 308 representing the compressed digitizedvoice signal is coupled to the serial output circuitry 296.

For a predetermined period of time after either the dataform readingtrigger 36 is depressed to initiate a dataform reading session (dataformreading mode) or the imaging trigger 28 is depressed to initiate a imagecapture session (imaging mode), the control and selection circuitry 284monitors the image capture trigger switch 28. If the operator depressesthe trigger 28 during the predetermined period, the voice capture module304 and voice compression circuitry 306 are activated for verbal input.As long as the operator keeps the trigger depressed, the voice capturemodule 304 and voice compression circuitry 306 will remain activated sothat the operator can speak into the microphone 34 and provideinformation concerning an item whose image was captured or whosedataform was read which will be transmitted and/or stored with thecorresponding image or decoded dataform. Normally, the voice capturemodule 304 will be used subsequent to an imaging session where theoperator wants to communicate to supervisory personnel reviewing thecaptured image some additional information concerning the imaged itemsuch as the item's location, a short description of the problem with theitem, etc. The voice compression circuitry 306 utilizes one of a numbervoice compression algorithms well known to those skilled in the art.

Decoded dataform data 298, compressed image data 300 and compresseddigitized voice data 308 are routed to the serial output circuitry 296which assembles output data 310 for serial output through a serialoutput port 312. In portable data collection device 10 of the presentembodiment the serial output port 312 is coupled to an input port of aradio module 314 mounted on the control and decoder board 22 (shownschematically in FIG. 5). The radio module 314 modulates and transmitsthe output data 310 to a remote device (not shown) where the transmitteddata is demodulated. The demodulated output data may be used to updateinventory, and/or accounting records, update production controlexpediting or product tracking files, permit supervisory correctiveaction to remove/repair damaged items, etc.

The control and decoder board 22 further includes exposure parameterscontrol circuitry 316 which outputs control signals 318, 320 to theexposure period control circuitry 254 and the gain control circuitry 252of the camera assembly 38 and a signal 322 embodying an appropriate setof reference voltages for operating the A/D converter 272. The exposureparameters control circuitry 316 includes fuzzy logic circuitry 324which analyzes captured frames of data accessed from the frame buffermemory 274. The fuzzy logic circuitry 324 analyzes a captured frame todetermines if the current exposure period of the 2D photosensor array48, the current amplification of the video signal 250 by the gaincontrol circuitry 252 and the reference voltages used by the A/Dconverter circuitry 272 are resulting in an “acceptable” captured imageframe. If not, the control signal 318 is changed to adjust the exposureperiod of the 2D photosensor array 48 and/or the control signal 320 ischanged to adjust the amplification of the video signal 250 and/or thesignal 322 is changed to adjust the operation of the A/D convertercircuitry 272. After the adjustment, another captured frame is analyzedby the fuzzy logic circuitry 324 and, if necessary, further adjustmentsare made in an iterative fashion until the camera assembly 32 producesan “acceptable” captured image. A suitable exposure parameter controlcircuit including fuzzy logic control circuitry is disclosed in U.S.Pat. No. 5,702,059, previously referenced

As can be seen in FIGS. 10 and 34A, the power source 24 is coupled tothe control and decoder board 22 to provide operating power to themicroprocessor 266 and other circuitry mounted on the board and theradio module 314. Power circuitry 326 under the control of themicroprocessor 266 is coupled through a lead 328 to the illuminationassembly 42 and the camera assembly 38 to supply power to thesecomponents of the imaging assembly 18.

The flow chart shown in FIG. 35 illustrates the operation of the imagingassembly 18 in the dataform decoding mode and a first operatingembodiment of the imaging mode. In the first operating embodiment of theimaging mode, a single frame of the image in the target area 44 iscaptured, compressed and output when the operator depressed the imagingtrigger 28. The flow chart shown in FIG. 36 illustrates the operation ofthe imaging assembly 18 in the dataform decoding mode and a secondoperating embodiment of the imaging mode. In the second operatingembodiment of the imaging mode, successive frames of the image in thetarget area 44 are captured, compressed and output as long as theoperator has the imaging trigger 28 depressed. The flowchart in FIG. 37illustrates a third operating embodiment in which the imaging assemblyis actuated in the dataform reading mode and to decode a dataform withinthe image area and to capture the digital image dataform selected imagearea such as a signature box. The imaging system 18 determines aposition of the dataform in the target area and then determines theposition of the signature box. The digital image data corresponding tothe portion of the image area including the signature box is output ineither compressed or noncompressed form through the serial output port312.

The imaging mode is advantageously employed when the operator using theportable data collection device 10 notices the item 46 is damaged, outof place, incomplete, etc. The imaging mode of the imaging assembly 18is used to capture an image of the item 46 and, using the radio module314, transmit the captured image to a remote device accessible bysupervisory personnel so that the problem may be ascertained bysupervisory personnel and appropriate corrective action taken, e.g.,deletion of item from inventory records, issuance of order to removeitem from storage location and return to production facility or vendorfor rework/repair, moving item to proper location, filing insuranceclaim, etc.

Turning to the first operating embodiment of the imaging mode shown inFIG. 35, at 400 the imaging assembly 18 waits for a signal representingeither actuation of the imaging trigger 28 or the dataform readingtrigger 26 to commence either an image capture session or a dataformreading session. The signal may be generated by the image capturetrigger circuit 28 a, the dataform reading trigger circuit 26 a or by asignal generated by customer specific application software. At 402, uponreceiving an appropriate signal, the imaging assembly 18 is activatedand a frame of image data captured and stored in the frame buffer memory274.

At 404, the fuzzy logic circuitry 324 determines if the captured imageframe is acceptable, that is, the image is within predeterminedacceptable ranges for brightness and the magnitude of charges on thephotosensors of the 2D photosensor array 48. If the fuzzy logiccircuitry 324 determines the captured frame is not acceptable, one ormore of the operating parameters of the camera assembly 38 and the A/Dconverter circuitry 272 are modified as shown at step 406. The looprepresented by steps 402, 404, 406 are repeated until the captured frameis determined to be acceptable.

At step 408, if the control and selection circuitry 284 determines thatthe activation signal is from the dataform reading trigger 26 requiringa dataform decode, the captured frame is coupled to the image processingand decoder circuitry 290 for attempted decoded of the dataformrepresented in the captured frame. At step 410, the decoding circuitry292 attempts to decode the dataform represented in the captured frame.At step 412, a determination is made if the decoding was successful. Atstep 414, if the decoding was successful, the extracted decoded data isoutput to the serial output circuitry 296 and at step 416, the green LEDindicator 32 is energized for a predetermined time to signal theoperator that the dataform 45 in the target area 44 has beensuccessfully read. Subsequently, the imaging assembly 18 is turned off.

If at step 412, the decoding was not successful, the selection circuitryat energizes the red LED indicator 30 for a predetermined time to signalto the operator that the decoding was unsuccessful and that he or sheshould continue to point the device 10 at the dataform 45 in the targetarea 44. The process returns to step 402 where another image frame iscapture and the remaining steps are repeated.

If at step 408, the control and selection circuitry 284 determines thatthe activation signal is from the imaging trigger 28, the captured frameis routed to image compression circuitry 294 to compress the data in thecaptured frame, shown at step 418. At step 420, the compressed imagedata is output to the serial output circuitry 296 and the green LEDindicator 32 is energized to signal the operator that the image in thetarget area 44 has been successfully captured.

Referring to FIG. 36, in a second operating embodiment of the imagingmode, successive frames of an image of the target area 44 are capturedfor as long as the operator maintains the imaging trigger 28 depressed.This operating embodiment would be advantageous in situations where theitem 46 which the operator wishes to image because of some defect,damage, etc., is very large compared to the area of the target area 44.Therefore, capturing a single image frame and transmitting a signalcorresponding to the captured frame to a remote device or supervisoryreview may not provide supervisory personnel with an image covering alarge enough portion of the item 46 to ascertain the problem anddetermine appropriate corrective action. By capturing successive framesduring the period that the operator keeps the imaging trigger 28depressed, the operator may move the portable data collection device 10with respect to the item 46 to provide a video image of the completeitem (or an image of as much of the item as necessary to provide foridentification of the item and the item's problem).

For this embodiment, the process remains generally the same as theembodiment described in connection with FIG. 35. However, after theoutput of compressed data to the serial output circuitry 296 at step420, the control and selection circuitry 284, at step 422, checks to seeif a signal has been received from the image capture trigger circuitry28 a indicating that the operator has released the imaging trigger 28.If such a signal from the image capture trigger circuitry 28 a has beenreceived, then at 424, the control and selection circuitry 284 energizesthe green LED indicator 32 for a predetermined time period to signal theoperator that the image in the target area 44 has been successfullycaptured. Subsequently, the imaging assembly 18 is turned off.

If no signal is received from the image capture trigger circuitry 28 aindicating that the operator has released the imaging trigger 28, thenthe process loops back to step 402 and successive image frames arecaptured, compressed and output to the serial output circuitry 296 untilsuch time as the control and selection circuitry 284 received the signalfrom the image capture trigger circuitry 28 a indicating that theimaging trigger 28 has been released.

As can best be seen in FIGS. 10 and 34, the imaging assembly 18 includesthe camera assembly 38 which is electrically coupled to the control anddecoder board 22. The control and decoder board 22 includes themicroprocessor 266 and associated circuitry. The circuitry of theimaging assembly 18 may by embodied in software resident in one or moreRAM or ROM memory chips 430 (FIG. 5) mounted on the control and decoderboard 22 and operated by the microprocessor 266. Alternately, thecircuitry of the imaging assembly 18 may comprise separateapplication-specific integrated circuitry (ASIC) mounted on the controland decoder board 22.

In the third operating embodiment of the portable data collection device10 of the present invention, the dataform decoding mode is actuated tocapture, compress and output an image contained within the boundary ofan image area associated with a dataform. For example, the desired imagearea may be a signature block positioned a predetermined distance from adataform. In FIG. 33, a signature block 432 is associated with a 2Ddataform 434 known as MaxiCode (MaxiCode™ is a symbology standard ofUnited Parcel Service). The signature block 420 is positioned at apredetermined location with respect to the dataform 434.

The dataform 434 is imprinted on a label affixed to a package to bedelivered to a recipient. When the package is delivered, the recipientsigns his or her signature 436 within a perimeter of the signature block420. To document delivery of the package, the portable data collectiondevice imaging assembly 18 is actuated with the dataform reading trigger28 to image and decode the dataform 434. However, in addition todecoding the dataform 434, it would be desirable to store a portion ofthe captured image corresponding to the image within the signature block320 to prove the recipient's acknowledgement of receipt of the package.

In the third operating embodiment, the imaging assembly 18 will capturean image of the target area 44 including both the dataform 434 and thesignature block 420. The output data sent to the serial output circuitry296 will include the decoded dataform and a compressed digital image ofthe image within the signature block 420, i.e., the signature 436.

FIG. 37 is a flowchart summarizing this third operating embodiment. Atstep 500, the imaging assembly 18 waits for the start of a dataform readsession which is typically initiated by the operator pulling thedataform reading trigger switch 26. After imaging the target area 44, atstep 502, a frame of an image of the target area 44 is captured and adigital representation is stored in the frame buffer memory 274. Thefuzzy logic control circuitry 324 determines if the captured image frameis acceptable for decoding at step 504. If the frame is not acceptable,parameters are adjusted at step 506.

If the captured image frame is acceptable for decoding at step 508, thedecoding circuitry 292 attempts to decode cell data values associatedwith illumination intensity data values stored in the frame buffermemory 274. At step 510, if the cell data values are decodeable, then,at step 512, decode of the dataform 434 occurs. The signature block 420is located at a predetermined position with respect to the dataform 434,that is, the location, size and/or orientation of the signature block420 with respect to the dataform 434 is fixed. Data representative ofthe predetermined position may be encoded in the dataform or may bepreprogrammed into the portable data collection device's applicationsoftware. Also included in the dataform are certain distinguishingfeatures that permit locating the dataform 434 in the target area, forexample, the “bulls eye” mark at the MaxiCode center.

Other dataform formats would include different distinguishing featuressuch a guard bar for PDF-417 or Super Code dataforms or orientationmarkers for data matrix dataforms. As a result of the predeterminedposition data in conjunction with the distinguishing features of thedataform, the location, size and/or orientation of the signature block420 within the target area 44 is determined at step 514, is determined.At step 516, a digital representation of the portion of the imagecorresponding to the signature block 420 is coupled to the imagecompression circuitry 294 for data compression.

The compressed image data representing the signature block 420 and atleast a portion of the decoded dataform data are output to the serialoutput circuitry 296, at step 518, for subsequent transmission by theradio module 314 to a remote device. At step 520, the green LED 32 isenergized for a predetermined time signaling to the operator that thedataform 434 was successfully decoded and an image of the signatureblock 420 was successfully captured and output, to the serial outputcircuitry 296. If the captured frame is not decodeable at step 510, thered LED 30 is energized for a predetermined time to inform the operatorthat the read was unsuccessful and to maintain the dataform readingtrigger 26 depressed and keep the data collection device 10 aimed at thedataform 434 until a successful read is obtained.

It should be appreciated that because the predetermined positional datafor a desired image area such as a signature block located at apredetermined position with respect to a dataform may be preprogrammedinto the portable data collection device, digital image data of aportion of the desired image area may be output without the necessity ofdecoding the dataform. After storing a digital representation of thetarget area 44 and locating the distinguishing features of the dataform434, the location of the signature block 420 can be calculated based onthe pre-programmed predetermined position data and the location of thedistinguishing features of the dataform.

Regardless of whether predetermined positional data is preprogrammedinto the data collection device 10 or encoded in the dataform. Therewill be uses for the device 10 this invention wherein only some of thecodes will have associated desired image areas. Therefore, it isdesirable for a dataform to include an indication as to whether thereexists an associated desired image area to be captured and output. Theindication may be encoded in the dataform or the dataform format itselfmay be the indication. For example, all MaxiCode formats may be known tohave an associated desired image area which is to be captured andoutput.

In the signature block placement of FIG. 33, the block is centered belowthe dataform 434 at a distance “g” from the dataform. The height of theblock is H and the width is W. The dataform is of a predetermined sizehaving a height “Y”. To locate the signature block 420 in the targetfield 44, coordinate locations of the center (x_(c), y_(c)) and theheight of the dataform “Y” are determined in the pixel coordinatedomain. Then, the formulas for calculating the positions of the fourcorners of the signature box in the pixel coordinate domain are asfollows:

Upper-left corner: (x _(l) −x _(c) , y _(u) −y _(c))=(−W/2, Y/2+g)

Upper-right corner: (x _(r) −x _(c) , y _(u) −y _(c))=(−W/2, Y/2+g)

Lower-left corner: (x _(l) −x _(c) , y _(l) −y _(c))=(−W/2, Y/2+g+H)

Lower-right corner: (x _(r) −x _(c) , y _(l) −y _(c))=(−W/2, Y/2+g+H)

The formulas to correct each x or y value for angular rotation θ is asfollows:

(x ^(l))=(cos θ−sin θ) (x−x _(c))+(x _(c))

(y ¹)=(sin θ−cos θ) (y−y _(c))+(y _(c))

First Alternate Embodiment of Focusing Assembly of Optic Assembly

An alternate embodiment of the focusing assembly is shown in FIG. 42generally at 900. Components that have the same structure as thecorresponding components described with respect to the focusing assembly800 disclosed above will be assigned reference numbers followed by aprime (′) which are the same as corresponding reference numbers in thefirst embodiment. For example, the focusing optic 810′ of the focusingassembly 900 is identical in structure and function as the focusingoptic 810 of the focusing assembly 800. The focusing assembly 900includes a focusing optic 810′ comprising two wedge shaped lens 820′,830′ which are congruent in shape and supported in a lens supportfixture (not shown but identical to the lens support fixture 840 of thefocusing assembly 800 described above). The lens 820′ is moveable withrespect to the lens 830′ along a path of travel T′ to change thethickness t′ of the focusing optic 810′ as described above with respectto lens 820, 830 in the focusing assembly 800.

The focusing assembly 900 includes a drive assembly 960 to move themoveable lens 820′ along the path of travel T′. The drive means 960includes a rod 962 having one end 964 attached to a base surface 829′ ofthe lens 820′. An opposite end 966 of the rod 962 defines a pin 968extending vertically above and below upper and lower surfaces of the rod962. A V-shaped pivoting member 970 includes an oval shaped opening 972in an end portion of one arm 974. The end portion of the arm 974 isdefines a slotted opening 975 as can best be seen in FIG. 42A. The endportion 966 of the rod 962 fits within the slotted opening 975 and pin968 slidingly fits within the oval shaped opening 972 to pivotallysecure the rod 962 to the V-shaped pivoting member 970. A second arm 976of the V-shaped pivoting member 970 includes a pin 978 which slideswithin a slot shaped opening 979 in a rearward facing portion of aslider 980. The V-shaped pivoting member 970 is supported on a verticalpost 982 extending from an inner surface 16 a of the housing snout 16.The V-shaped pivoting member 970 pivots about a pin 984 extendingvertically upwardly from the post 982.

A portion 986 of the slider 980 extends through a slotted opening 988 ina side of the snout 16. The slider 980 is slidably confined between apair of parallel ledges 990, 992 which extend outwardly from the innersurface 16 a of the housing snout 16. The ledges have vertical lipportions 990 a, 990 b (FIG. 42A) to further confine the slider 980. Asthe slider portion 986 is moved along the slotted opening 988 in adirection labeled R in FIG. 42, the V-shaped pivoting member 970 pivotsin a clockwise direction labeled C about the pin 984. This causes therod 962 to move in direction labeled D and also causes the moveable lens820′ to move in the direction D along its path of travel T′. Movement ofthe lens 820′ in the direction D causes the thickness t′ of the focusingoptic 810′ to increase.

Second Alternate Embodiment of Focusing Assembly of Optic Assembly

A second alternate embodiment of the focusing assembly is shown in FIG.43 generally at 1000. Again, components that have the same structure asthe corresponding components described with respect to the focusingassemblies 800, 900 disclosed above will be assigned reference numbersfollowed by a double prime (″) which are the same as correspondingreference numbers in the first embodiment. For example, the focusingoptic 810″ of the focusing assembly 1000 is identical in structure andfunction as the focusing optic 810 of the focusing assembly 800. Thefocusing assembly 1000 includes a focusing optic 810″ comprising twowedge shaped lens 820″, 830″ which are congruent in shape and supportedin a lens support fixture (not shown but identical to the lens supportfixture 840 of the focusing assembly 800 described above). The lens 820′is moveable with respect to the lens 830′ along a path of travel T″ tochange the thickness t″ of the focusing optic 810′ as described abovewith respect to lens 820, 830 in the focusing assembly 800. The focusingassembly 1000 includes a drive assembly 1060 to move the moveable lens820″ along the path of travel T″. The drive means 1060 includes astepper motor 1062 having a pinion gear 1064 mounted to one end of themotor shaft 1066. A rack 1070 is coupled to an end 829″ of the moveablelens 820″. A drive portion 1072 of the rack 1070 includes linear gearingthat meshes with the pinion gear 1064 of the stepper motor 1062. Therack 1070 slides in a grooved portion of a support 1074 extending fromthe modular housing 20. The stepper motor 1062 is configured toprecisely rotate the motor shaft 1066 in either the clockwise orcounterclockwise directions in increments (or steps) of 1/36 of arevolution (10 degree increments) thus providing precise control overthe position of the lens 820″ along its path of travel T″.

The stepper motor 1064 is controlled by focusing circuitry 1080 mountedon the control and decoder board. As be seen schematically in FIG. 44A,the focusing circuitry 1080 receives input from the frame buffer memory274 an analyzes the sharpness of successive captured image frames. Whenthe focusing circuitry 1080 determines that the sharpness of a capturedframe has fallen below a predetermined value, the circuitry takescorrective action by moving actuating the stepper motor 1062 androtating the shaft 1066 in 10 degrees increments such that the rack 1070moves the lens 820″ in a predetermined direction along its path oftravel T″. Captured frames are continuously analysed by the focusingcircuitry, when the sharpness of a captured image frame exceeds thepredetermined value, the rotation of the shaft 1066 is halted by thefocusing circuitry 1080 and the lens 820″ remains stationary so long asframe sharpness continues to exceed the predetermined image sharpnessvalue.

If acceptable sharpness is not achieved by the time the lens 820″reaches an endpoint along it path of travel T″, the focusing circuitry1080 reverses the rotation of the stepper motor shaft 1064 and moves thelens 820″ in a direction toward its opposite path of travel endpoint.When the sharpness of a captured image frame exceeds the predeterminedimage sharpness value, movement, rotation of the shaft 1066 is halted asexplained above.

Alternate Embodiment of Illumination Assembly

An alternate embodiment of an illumination assembly suitable for use inthe modular portion 20 of the imaging assembly 18 of the portable datacollection device 10 is shown generally at 800 in FIG. 19. Theillumination assembly 700 includes a printed circuit board assemblysimilar to the printed circuit board assembly 60 described above. Forsimplicity, the same reference numbers are used to identify componentsof the printed circuitry board assembly shown in FIG. 11 correspondingto the printed circuit board assembly 60 described above. Referring toFIG. 19, the printed circuit board assembly 60 includes a plurality ofsurface mount exposure illumination LEDs 66. A single piece acrylic orpolycarbonate lens array 802, fabricated, preferably, from PMMA ispositioned between the printed circuit board assembly 60 and the targetarea 44 (FIGS. 5 and 10) for directing the illumination from theexposure LEDs 66 towards the target area 44. The lens array 802 issimilar to the lens array 62 but provides for generation of a targetingillumination frame pattern FR (FIG. 32) which frames or surrounds thegenerated illumination crosshair pattern CR discussed in connection withthe lens array 702. As can be seen in FIG. 10 with respect to thepreviously described lens array 62, the lens array 802 functions as afront panel for the modular portion 20 of the imaging assembly. Theprinted circuit board assembly 60 includes printed conductors and apower lead 112 operative for supplying power to the illumination LEDs66. A suitable surface mount illumination LED is produced by theMarkTech Corporation of Latham, N.Y., as Part No. MTSM735K-UR orMTSM745KA-UR. Each illumination LED 66 provides illuminosity of 285milli candela (mcd) over an angular illumination field of about 68degrees. The small footprint of each illumination LED 66 enables fourLEDs to be placed in a row measuring less than 14 mm. The printedcircuit board assembly 60 includes four banks of four illumination LEDs66 totaling sixteen illumination LEDs providing 4560 mcd of uniformillumination over the target area 44. A central opening 67 in theprinted circuit board assembly 60 provides an opening for the shroud 58to extend through.

The lens array 802 includes four illumination optic portions 808 a, 808b, 808 c, 808 d (FIG. 39) which are identical in dimension and opticprescription to the illumination optic portions 88 a, 88 b, 88 c, 88 dof lens array 62. Each of the illumination optic portions 808 a, 808 b,808 c, 808 d are aligned with a corresponding bank of illumination LEDs66. The illumination optic portions 808 a, 808 b, 808 c, 808 d direct a68 degree angular illumination field from each illumination LED 66 intoa uniform field having an angular field of view which substantiallycorresponds to the angular field of view of the optic assembly 43 whichdefines the target area 44.

Referring to FIGS. 24 and 26, which show a horizontal cross section(FIG. 24) and a vertical cross section (FIG. 26) through theillumination optic portions 808 a, 808 b, 808 c, 808 d, it can be seenthat each optic portion comprises a lens including four verticallyoriented cylindrical entry optic surfaces 816 extending from a back side817 (FIG. 24) of the lens array 802. One vertically oriented cylindricalentry surface 816 is positioned in front of a corresponding LED 66. Eachoptic portion 808 a, 808 b, 808 c, 808 d also includes a horizontallyoriented cylindrical optic exit surface 818 extending from a front side819 (FIG. 22) of the lens array 802. One horizontally orientedcylindrical exit optic surface 818 is positioned in front of each bankof four LEDs 66. The vertically oriented cylindrical entry opticsurfaces 816 define the horizontal field of illumination and thehorizontally oriented cylinders 818 define the vertical field ofillumination. This arrangement provides an even illumination intensitydistribution across the target area 44. The 4560 mcd of illuminationprovided by the illumination LEDs 66 will provide an illuminationintensity in excess of 106 lux when the target object 45 is at adistance of 8.5 inches from the optic surface 90 of the lens 43 a. Thevertically oriented entry surfaces 816 have a radius of curvature of2.50 mm. and a height I (FIG. 23) of 4.00 mm while the horizontallyoriented exit surfaces 818 have a radius of curvature of 3.00 mm. and awidth J (FIG. 24) of 13.75 mm. Referring to FIGS. 24-26, suitabledimensions for the lens array 802 are as follows:

Label Description Dimension A Height of lens array 802 21.75 mm. B Widthof lens array 802 39.55 mm. C Diameter of center opening 12.00 mm. 820of lens array 802 D Height between middle of 14.13 mm. vertical entrysurfaces 816 E Thickness of lens array 802  1.95 mm. F Maximum extensionof aspheric  1.75 mm. light exit surfaces 726, 730 from back side 717 ofG lens array  5.25 mm. Distance between maximum extension of asphericlight exit surfaces 726, 730 and center of respective segmented lightexit surfaces 728, 732 along centerlines T-T H Distance betweencenterlines T-T  7.80 mm. and outer edge of lens array 702 I Height ofvertically oriented entry  4.00 mm. surfaces 816 J Width of horizontallyoriented exit 13.75 mm. surfaces 718

Referring again to FIG. 19, the illumination assembly also includes atargeting arrangement or assembly to aid in aiming the device 10 at thetarget object 45. The targeting assembly includes the targeting LEDilluminators 64 a, 64 b, which extend into apertures 68, 70 in theprinted circuit board assembly 60 and, when energized, projectillumination into first and second targeting optics 822, 824respectively of the lens array 62. The first and second targeting optics822, 824 are mirror images of each other and are identical inconfiguration.

As shown in FIG. 30, the targeting optic 822 generates a crosshairpattern of illumination CR1 and a half frame FR1 pattern ofillumination. As shown in FIG. 31, the targeting optic 824 generates acrosshair pattern of illumination CR2 and a half frame pattern ofillumination FR2. When the device is properly focused on the targetobject 45 at the minimum best focus position MIN S2 of the opticassembly 43 and properly oriented such that the lens array 802 issubstantially parallel with the target object 45, the crosshair patternsof illumination CR1, CR2 coincide or overlap to form a crosshair patternof illumination CR, just like the crosshair pattern CR formed by thelens array 702. As can be seen in FIG. 32, the crosshair pattern CR ischaracterized by a horizontal portion of width w (18 mm.), a verticalportion of height h (18 mm.) and a thickness of the pattern ofillumination of t. Furthermore, the half frame patterns of illuminationFR1, FR2 are configured as complementary halves of a rectangle whichform a full frame pattern of illumination FR as shown in FIG. 32 whichframes or surrounds the crosshair pattern CR Like the crosshair patternof illumination, the frame pattern of illumination FR is not a line butan illumination intensity pattern having a thickness represented in FIG.32 by the distance labeled T. At the minimum best focus position MIN S2,the frame pattern of illumination FR has a vertical height of 60 mm.labeled H in FIG. 32 which is substantially equal to the height of thetarget area 44 at the minimum best focus position MIN S2 and ahorizontal span of 80 mm. labeled W in FIG. 32 which is substantiallyequal to the width of the target area 44 at the minimum best focusposition MIN S2.

The first and second targeting optics 822, 824, which are identical inconfiguration, are shown in cross section in FIGS. 25 and 26. The firsttargeting optics 822 comprises a lens with an aspherical light entryoptic surface 826 and a segmented cylindrical light exit optic surface828. The second targeting optics 824 comprises a lens with an asphericallight entry optic surface 830, similar to the aspherical light entryoptic surface 826, and a segmented cylindrical light exit optic surface832, similar to the segmented cylindrical light exit optic surface 828.

The aspherical entry surfaces 826, 830 each have a diameter of 8 mm., aradius of curvature of 2.890 mm. and a conic constant of −2.534. Thesegmented cylindrical light exit surfaces 828, 832 each have an 8.0 mm.by 8.0 mm. square shaped outer perimeter. The segmented cylindricalsurface 828 is comprised of four triangular shaped sections 840, 842,844, 846 (FIG. 22) while the segmented cylindrical surface 832 isdivided into four triangular shaped sections 850, 852, 854, 856, whereinsections 840 and 850 are identical, sections 842 and 852 are identical,sections 844 and 854 are identical and 846 and 856 are identical.

The upper triangular section 840 comprises a vertically orientedcylindrical light exit optic surface with a triangular shaped cornerregion 860 having a horizontally oriented cylindrical light exit opticsurface (radius of curvature 25.00 mm.) in the upper left hand corner asseen in FIG. 22. The vertically oriented cylindrical light exit opticsurface of the upper triangular section 840 (not including the cornerregion 860) is similar in optic configuration to upper triangularsection 740 described above.

The lower triangular section 844 also comprises a vertically orientedcylindrical light exit optic surface with a triangular shaped cornerregion 864 having a horizontally oriented cylindrical light exit opticsurface (radius of curvature 25.00 mm.) in the lower left hand corner asseen in FIG. 22. The vertically oriented cylindrical light exit opticsurface of the lower triangular section 844 (not including the cornerregion 864) is similar in optic configuration to lower triangularsection 744 described above.

The right triangular section 842 comprises a horizontally orientedcylindrical light exit optic surface and is similar in opticconfiguration to the right triangular section 742 discussed above. Theleft triangular section 846 comprises a horizontally orientedcylindrical light exit optic surface with first and second triangularregions 866, 867. The horizontally oriented cylindrical light exit opticsurface of the left triangular section 846 (not including the cornerregions 866, 867) is similar in optic configuration to the lefttriangular section 746 discussed above. The triangular region 866 isadjacent triangular corner region 860 and comprises a verticallyoriented cylindrical light exit optic surface (radius of curvature 25.00mm.). The triangular region 867 is adjacent triangular corner region 864and comprises a vertically oriented cylindrical light exit optic surface(radius of curvature 25.00 mm.).

The upper triangular section 850 comprises a vertically orientedcylindrical light exit optic surface with a triangular shaped cornerregion 870 having a horizontally oriented cylindrical light exit opticsurface (radius of curvature 25.00 mm.) in the upper right hand corneras seen in FIG. 22. The vertically oriented cylindrical light exit opticsurface of the upper triangular section 850 (not including the cornerregion 870) is similar in optic configuration to upper triangularsection 750 described above.

The lower triangular section 854 also comprises a vertically orientedcylindrical light exit optic surface with a triangular shaped cornerregion 874 having a horizontally oriented cylindrical light exit opticsurface (radius of curvature 25.00 mm.) in the lower right hand corneras seen in FIG. 22. The vertically oriented cylindrical light exit opticsurface of the lower triangular section 854 (not including the cornerregion 874) is similar in optic configuration to lower triangularsection 754 described above.

The left triangular section 852 comprises a horizontally orientedcylindrical light exit optic surface and is similar in opticconfiguration to the left triangular section 752 discussed above. Theright triangular section 856 comprises a horizontally orientedcylindrical light exit optic surface with first and second triangularregions 876, 877. The horizontally oriented cylindrical light exit opticsurface of the right triangular section 856 (not including the cornerregions 876, 877) is similar in optic configuration to the righttriangular section 756 discussed above. The triangular region 876 isadjacent triangular corner region 870 and comprises a verticallyoriented cylindrical light exit optic surface (radius of curvature 25.00mm.). The triangular region 877 is adjacent triangular corner region 874and comprises a vertically oriented cylindrical light exit optic surface(radius of curvature 25.00 mm.).

The optic surfaces of the corner regions 860, 864, 866, 867 are tiltedwith respect to the optic surfaces of their corresponding triangularsections 840, 844, 846 such that illumination from the targeting LED 64a is focused through the corner region optic surfaces to generate thehalf frame illumination pattern FRI. Similarly, the optic surfaces ofthe corner regions 870, 874, 876, 877 are tilted with respect to theircorresponding triangular sections 850, 854, 856 such that illuminationfrom the targeting LED 64 b is focused through the corner region opticsurfaces to generate the half frame illumination pattern FR2. The tiltangles of corner regions 860 and 866 will be examined. The same tiltangles are correspondingly used for all the other corner regions and thediscussion will not be repeated for each region.

Prior to discussing the tilt angles of the corner regions 860, 864, itis important to note that the light exit optic surfaces of thetriangular sections 840, 842, 844, 846, 850, 852, 854, 856 have opticalsurfaces with the angle of tilt (9.85 degrees) discussed in detail withrespect to the lens array 702 above. Thus, the triangular sections 840and 846 have optical surfaces with a 9.85 degree angle of tiltdownwardly (as viewed in FIG. 25) toward the front side 819 of the lensarray 802.

The corner regions 860, 866 and the triangular sections 840, 846 aresymmetric about the diagonal line 880. As can best be seen in FIG. 25A,the optical surfaces of the corner regions 860, 866 are tilted at anangle labeled d of 11.50 degrees with respect to horizontal axis (axisL—L). The tilt angle of the corner regions is opposite of the tilt angleof the triangular sections 840, 846.

At the minimum best focus position MIN S2 of 140 mm. (5.5 inches) infront of the optic surface 90, the frame illumination pattern FR has anapproximate height h of 60 mm. (2.4 in.) and an approximate width w of80 mm. (3.2 in.) which corresponds to the dimensions of the target area44 at the best focus position S2. At the minimum best focus position MINS2, the target area 44 has a height of 62 mm. (2.4 in.) and a width of82 mm. (3.2 in.). As was the case in the illumination assemblyembodiment including the lens array 702, the crosshair illuminationpattern CR has a height of 18 mm . and a width of 18 mm . at the minimumbest focus position MIN S2.

While the description has described the currently preferred embodimentsof the invention, those skilled in the art will recognize that othermodifications may be made without departing from the invention and it isintended to claim all modifications and variations as fall within thescope of the invention.

In compliance with the statute, the invention has been described inlanguage more or less specific as to structural and methodical features.It is to be understood, however, that the invention is not limited tothe specific features shown and described, since the means hereindisclose comprise preferred forms of putting the invention into effect.The invention is, therefore, claimed in any of its forms ormodifications within the proper scope of the appended claimsappropriately interpreted in accordance with the doctrine ofequivalents.

What is claimed is:
 1. A portable data collection device comprising: a)a camera assembly, including an array of photosensor elements generatinga signal representative of an image of a target area, the imageincluding a dataform positioned in the target area; and b) an opticassembly positioned to focus illumination reflected from a generallyrectangular target area onto the array of photosensor elements, theoptic assembly including a focusing optic through which reflectedillumination from the target area passes, the focusing optic including amovable lens movable along a path of travel transverse to a central rayof the reflected illumination passing through the optic assembly,movement of the movable lens changing a best focus distance of the opticassembly wherein the best focus distance corresponds to a distancebetween the device and the dataform which results in a clear image ofthe dataform being focused onto the array of photosensor elements. 2.The portable data collection device of claim 1 wherein the focusingoptic includes the moveable lens and a stationary lens configured suchthat moving the moveable lens with respect to the stationary lens alongthe path of travel of the moveable lens changes the thickness of thefocusing optic through which the reflected light passes andcorrespondingly changes the best focus distance.
 3. The portable datacollection device of claim 2 wherein the moveable lens and thestationary lens are comprised of wedge shaped pieces of glass eachhaving an inclined surface and wherein the inclined surfaces are insliding contact.
 4. The portable data collection device of claim 3wherein the focusing optic is part of a focusing assembly which includesstructure operatively connected to the moveable optic to move themoveable lens along its path of travel.
 5. The portable data collectiondevice of claim 1 further including an illumination assembly directingillumination towards the target area, the illumination assemblyincluding a targeting arrangement for directing an illuminationtargeting pattern aid in aiming the portable data collection device, thetargeting arrangement including first and second targeting lightemitting diodes and first and second targeting optics, the firsttargeting optics positioned adjacent the first targeting light emittingdiode and generating a first illumination targeting pattern and thesecond targeting optics positioned adjacent the second targeting lightemitting diode and generating a second illumination targeting pattern,the first and second targeting pattern substantially coinciding to forma single illumination targeting pattern when the device is at a minimumdistance best focus position.
 6. The portable data collection device ofclaim 5 wherein the first targeting optics includes a light entry opticsurface facing the first targeting light emitting diode and a light exitoptic surface directed toward the target area and wherein the secondtargeting optics includes a light entry optic surface facing the secondtargeting light emitting diode and a light exit optic surface directedtoward the target area and further wherein the light entry opticsurfaces of each of the first and second targeting optics compriseaspheric optic surfaces.
 7. The portable data collection device of claim6 wherein the light exit optic surface of each of the first and secondtargeting optics comprise a plurality of cylindrical surfaces.
 8. Theportable data collection device of claim 5 wherein the first and secondtargeting optics are supported in a panel having a generally planarfront surface which faces the target area and wherein the light exitoptic surface of each of the first and second targeting optics is tiltedwith respect to the generally planar front surface of the panel.
 9. Theportable data collection device of claim 8 wherein an angle of tilt ofthe first targeting optics light exit optic surface with respect to thegenerally planar front surface of the panel is substantially equal to anangle of tilt of the second targeting optics light exit optic surfacewith respect to the generally planar front surface of the panel.
 10. Theportable data collection device of claim 9 wherein the first targetingoptics light exit optic surface comprises first and second verticallyoriented cylindrical optic surfaces and first and second horizontallyoriented cylindrical optic surfaces and wherein the targeting patterngenerated by the first targeting optics is a crosshair pattern andfurther wherein the second targeting optics light exit optic surfacecomprises first and second vertically oriented cylindrical opticsurfaces and first and second horizontally oriented cylindrical opticsurfaces and wherein the targeting pattern generated by the secondtargeting optics is a crosshair pattern.
 11. The portable datacollection device of claim 1 further including image processing anddecoder circuitry receiving the signal representative of the image ofthe target area and generating decoded data representative of thedataform.